132 LETTERS TO BROTHER JOHN. 



juice) is brought about in the same way as a co- 

 pious secretion of saliva was effected by its pre- 

 sence in the mouth. But, as there are neither 

 teeth nor tongue in the stomach, the food, when 

 there, cannot be so readily and at once mixed up, 

 and kneaded, as it were, with the gastric juice, as 

 it was by means of those instruments, comminuted 

 and commingled with the saliva in the mouth : it 

 is not, therefore, subjected all at once to the action 

 of the gastric juice, but gradually, layer after 

 layer. While the nutritious bolus is circumvolving 

 within the cavity of the stomach, the gastric juice, 

 poured out from the sides of the stomach, above 

 and around it, falls upon its surface. When its 

 upper surface or layer has been sufficiently acted 

 upon by the gastric juice when, by virtue of the 

 inherent properties of this juice, it has been con- 

 verted into a semi-fluid peculiar to itself, and called 

 "chyme" it floats off and away from the rest, towards 

 the lower part of the stomach, where it (the stomach) 

 is united to the upper extremity of the bowels. The 

 upper layer of the alimentary mass having been thus 

 converted into chyme by the action of the gastric 

 juice, and sent away from the remainder, the next 

 layer becomes exposed to the action of this juice; 

 and having, like the first, become converted into 



